1.Changsha University of Science and Technology;2.China West Construction Hunan Group Co.,Ltd
Aiming at the problems of high carbon emission and high cost of traditional backfilling materials, taking "green mine" as the concept, industrial solid wastes such as carbide slag, desulfurized gypsum and slag are used as cementitious components, and tailings are used as aggregates to prepare backfilling materials. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are used to study the hydration products and microstructure of the backfilling materials, and the working performance, mechanical properties and heavy metal solidification performance tests were carried out. The results show that: the setting time and fluidity of the developed backfilling materials meet the requirements of mine backfilling engineering. The maximum compressive strength of the backfilling body can reach 4.6Mpa and 7.9Mpa at 7d and 28d respectively, and the concentrations of Pb and Zn in the leaching solution of the backfilling body are lower than the specified limits. Calcium hydroxide in carbide slag provides alkaline environment, and desulfurization gypsum provides sulfate ion. The aluminosilicate material in slag is activated by both of them. A large number of needle like ettringite crystals and reticulated C-A-S-H gels interspersed with each other, and tightly bonded with tailings particles. With the extension of age, the structure became more compact, so that the backfilling body had good mechanical properties.